:root{color-scheme:light;--paper:#fffaf0;--ink:#302d2a;--muted:#6a5e51;--accent:#874421;--apricot:#ffe0ba;--yellow:#fff0b8;--surface:#fffefd;--border:#dac7ae;--focus:#754018;--dark-note:#513820;--line:#ecdcc4;--shadow:0 7px 0 #decdb766}
:root[data-theme="dark"]{color-scheme:dark;--paper:#25221d;--ink:#f8f1e5;--muted:#d1c2aa;--accent:#ffd59c;--apricot:#503925;--yellow:#473d25;--surface:#302b24;--border:#78654e;--focus:#ffd59c;--dark-note:#f8e1bd;--line:#504635;--shadow:0 7px 0 #08080740}
*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:1.5rem}body{margin:0;background:var(--paper);color:var(--ink);font-family:"Trebuchet MS",Calibri,Arial,sans-serif;font-size:1.125rem;line-height:1.65}button,a,summary{-webkit-tap-highlight-color:transparent}a{color:var(--accent);text-underline-offset:.2em}a:hover{text-decoration-thickness:2px}button{font:inherit}.page{max-width:1200px;margin:0 auto;padding:0 36px}.skip-link{position:fixed;z-index:10;left:12px;top:-90px;padding:12px 18px;background:var(--ink);color:var(--paper)}.skip-link:focus{top:12px}:focus-visible{outline:3px solid var(--focus);outline-offset:5px;border-radius:3px}.topbar{display:flex;align-items:center;justify-content:space-between;gap:20px;padding:24px 0 18px;border-bottom:1px solid var(--border);font-size:.95rem}.back-link{text-decoration:none;display:inline-flex;align-items:center;gap:10px;min-height:44px}.back-link:hover{text-decoration:underline}.theme-toggle{background:transparent;color:var(--muted);border:1px solid var(--border);padding:7px 15px;min-height:44px;border-radius:30px;font-size:.95rem;cursor:pointer}.theme-toggle[hidden]{display:none}.intro{display:flex;align-items:center;justify-content:space-between;gap:40px;padding:48px 0 36px}.eyebrow{font-size:.78rem;font-weight:bold;text-transform:uppercase;letter-spacing:.12em;color:var(--accent);margin:0 0 10px}h1{font-size:clamp(2.6rem,6.5vw,5rem);line-height:1.04;letter-spacing:-.04em;margin:0;color:var(--ink)}.title-mark{color:var(--accent)}.intro-lead{font-size:1.35rem;line-height:1.5;color:var(--muted);margin:23px 0 0}.notebook-note{align-self:center;min-width:240px;max-width:280px;background:var(--yellow);padding:23px 28px 24px;border:1px solid var(--border);border-radius:2px 2px 18px 2px;transform:rotate(3deg);box-shadow:var(--shadow)}.notebook-note p{margin:14px 0 0;font-size:1.08rem;line-height:1.55;color:var(--dark-note)}.notebook-note .drawing{width:90px;margin:0;background:white;border-radius:50%;border:6px solid white}.step-nav{display:flex;flex-wrap:wrap;gap:8px 25px;padding:15px 0 20px;border-bottom:2px solid var(--border)}.step-nav a{display:flex;align-items:center;gap:8px;min-height:44px;text-decoration:none;font-size:1rem;font-weight:bold;color:var(--ink)}.step-nav a:hover{text-decoration:underline}.step-nav a span{font-size:.8rem;background:var(--apricot);color:var(--accent);border-radius:50%;width:28px;height:28px;display:grid;place-items:center}.lesson-section{padding:52px 0 54px;border-bottom:1px solid var(--border);scroll-margin-top:20px}.section-heading{display:flex;align-items:flex-start;gap:20px;margin-bottom:24px}.step-number{font-size:3rem;line-height:1;letter-spacing:-.06em;color:var(--accent);opacity:.55;font-weight:bold;margin-top:22px}.section-heading h2{font-size:clamp(1.65rem,3vw,2.25rem);line-height:1.25;letter-spacing:-.025em;margin:0;max-width:900px}.section-lead{font-size:1.18rem;max-width:850px;margin:0 0 20px;color:var(--muted)}.partner-hint{border-left:4px solid var(--border);padding:4px 0 4px 17px;color:var(--muted);font-size:1rem;max-width:850px;margin:0 0 27px}.device-gallery{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:18px;margin:34px 0}.device-gallery figure{margin:0;min-width:0}.device-paper{height:235px;display:flex;align-items:center;justify-content:center;padding:16px 12px;background:#fff;border:1px solid var(--border);border-radius:5px}.device-gallery .drawing{max-width:100%;max-height:100%}.device-gallery .smartphone{width:122px}.device-gallery .washer{width:195px}.device-gallery .hearing{width:198px}figcaption{font-size:1.13rem;font-weight:bold;text-align:center;margin:15px -2px 0;line-height:1.3}figcaption small{display:block;color:var(--muted);font-size:.82rem;font-weight:normal;margin-top:7px;line-height:1.35}.drawing{overflow:hidden;position:relative;width:100%;background:white}.drawing img{display:block;position:absolute;max-width:none;height:auto}.laptop{aspect-ratio:536/456}.laptop img{width:286.567164%;left:-4.477612%;top:-7.017544%}.smartphone{aspect-ratio:291/463}.smartphone img{width:527.835052%;left:-217.869416%;top:-6.911447%}.washer{aspect-ratio:457/463}.washer img{width:336.105033%;left:-231.509847%;top:-6.911447%}.hearing{aspect-ratio:469/455}.hearing img{width:327.50533%;left:-5.33049%;top:-117.142857%}.magnifier{aspect-ratio:464/457}.magnifier img{width:331.034483%;left:-113.793103%;top:-116.630197%}.think-first{background:var(--yellow);padding:22px 28px;border-radius:3px 18px 18px 3px}.think-first p{margin:0 0 8px}.think-first p:last-child{margin-bottom:0}.think-first .sentence-starter{font-size:1.65rem;font-weight:bold;color:var(--accent);margin:14px 0}.next-link{display:inline-flex;gap:15px;align-items:center;margin-top:26px;font-size:1.02rem;font-weight:bold;min-height:44px}.next-link span{font-size:1.5rem}.device-facts{display:grid;grid-template-columns:1fr 1fr;gap:16px;align-items:start}.fact{background:var(--surface);border:1px solid var(--border);border-radius:8px;overflow:hidden}.fact summary{display:flex;align-items:center;justify-content:space-between;gap:15px;list-style:none;cursor:pointer;padding:24px;min-height:108px}.fact summary::-webkit-details-marker,details summary::-webkit-details-marker{display:none}.fact summary:hover{background:var(--yellow)}.fact-title{font-size:1.3rem;font-weight:bold;line-height:1.3}.small-label{display:block;color:var(--accent);text-transform:uppercase;font-size:.66rem;letter-spacing:.13em;margin:0 0 8px}.fact-title small{display:block;font-size:.8rem;font-weight:normal;color:var(--muted);margin-top:7px}.open-hint{display:flex;align-items:center;gap:12px;font-size:.8rem;color:var(--muted);flex-shrink:0}.plus{font-size:1.6rem;line-height:1;display:inline-block;font-weight:normal}.when-open{display:none}.fact[open] .when-open{display:inline}.fact[open] .when-closed{display:none}.fact[open]>summary{border-bottom:1px solid var(--border);background:var(--yellow)}.fact[open]>summary .plus,.discovery[open]>summary .plus{transform:rotate(45deg)}.fact-content{padding:8px 24px 24px;font-size:1.03rem;line-height:1.7}.fact-content p{margin:15px 0}.fact-content p:last-child{margin-bottom:0}.find-it{border-top:1px dashed var(--border);padding-top:16px;color:var(--accent)}.text-example{display:flex;align-items:center;justify-content:space-between;gap:8px;background:var(--paper);border:1px solid var(--border);border-radius:6px;padding:18px 15px;margin:24px 0}.example-label{display:block;font-size:.72rem;text-transform:uppercase;letter-spacing:.06em;color:var(--muted);margin-bottom:6px}.example-word{font-family:Consolas,"Courier New",monospace;font-size:1.6rem;white-space:nowrap}.cursor{font-weight:bold;color:var(--accent)}.key-step{display:flex;flex-direction:column;align-items:center;font-size:.68rem;line-height:1.4;gap:4px}.key-step kbd{font:inherit;font-weight:bold;font-size:.78rem;white-space:nowrap;border:1px solid var(--border);border-bottom-width:3px;padding:5px 7px;border-radius:4px;background:var(--surface)}.example-arrow{font-size:1.6rem;color:var(--accent)}.word-help{margin-top:24px;background:var(--apricot);border-radius:6px;border:1px solid var(--border)}.word-help summary,.answer summary,.credits summary{display:flex;align-items:center;justify-content:space-between;gap:15px;list-style:none;cursor:pointer;min-height:48px}.word-help summary{font-weight:bold;padding:15px 22px}.word-help dl{margin:0;padding:2px 24px 25px;display:grid;grid-template-columns:1fr 1fr;gap:20px 30px;font-size:1rem}.word-help dt{font-weight:bold;color:var(--accent)}.word-help dd{margin:4px 0 0}.thinking-pair{display:grid;grid-template-columns:1fr 1fr;gap:24px;margin-top:28px}.thinking-note{background:var(--surface);border:1px solid var(--border);border-top:6px solid var(--apricot);border-radius:4px;padding:24px 26px;display:flex;flex-direction:column}.question-topic{font-size:.78rem;text-transform:uppercase;letter-spacing:.08em;color:var(--accent);font-weight:bold;margin:0 0 9px}.thinking-note h3{font-size:1.18rem;margin:0}.thinking-note blockquote{font-size:1.38rem;line-height:1.45;font-weight:bold;margin:15px 0 20px;letter-spacing:-.015em}.thinking-note>p:not(.question-topic){font-size:1rem;margin:0 0 20px}.answer{margin-top:auto;border-top:1px dashed var(--border);font-size:1rem}.answer summary{padding-top:12px;font-weight:bold;color:var(--accent);font-size:.96rem}.answer>div{padding:0 0 4px}.answer p{margin:14px 0 0}.discovery{margin-top:28px;border:2px solid var(--border);border-radius:8px;overflow:hidden;background:var(--surface)}.discovery>summary{display:flex;align-items:center;justify-content:space-between;gap:20px;list-style:none;cursor:pointer;padding:25px 28px;background:var(--yellow);font-size:1.32rem;font-weight:bold;color:var(--accent)}.discovery-content{padding:7px 28px 28px;font-size:1.15rem}.discovery-content .key-sentence{font-size:1.58rem;line-height:1.4;font-weight:bold;color:var(--accent)}.device-result{font-size:1rem;border-top:1px dashed var(--border);padding-top:12px;margin-top:25px}.device-result p{margin:10px 0}.take-away{margin-top:42px}.take-away h3{font-size:1.5rem;line-height:1.25;margin:0 0 8px}.take-away>p{margin:0 0 20px;color:var(--muted);font-size:1rem}.download-links{display:grid;grid-template-columns:1fr 1fr;gap:16px}.download-links a{display:grid;grid-template-columns:1fr auto;gap:4px 18px;background:var(--apricot);border:1px solid var(--border);border-radius:6px;padding:17px 22px;text-decoration:none;line-height:1.4;color:var(--ink)}.download-links a:hover{background:var(--yellow)}.download-links a>span:first-child{font-size:1.06rem;font-weight:bold}.download-links a>small{grid-row:2;grid-column:1;color:var(--muted);font-size:.8rem}.download-links a>span:last-child{grid-row:1/3;grid-column:2;align-self:center;font-size:1.7rem;color:var(--accent)}.footer{display:flex;align-items:flex-start;justify-content:space-between;gap:20px;padding:26px 0 35px;color:var(--muted);font-size:.8rem}.footer>p{margin:10px 0}.footer>a{white-space:nowrap;margin-top:10px}.credits{max-width:480px}.credits 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@media(max-width:900px){.page{padding:0 25px}.intro{gap:25px}.notebook-note{min-width:210px;padding:20px}.device-gallery{grid-template-columns:repeat(2,minmax(0,1fr));gap:24px}.device-paper{height:235px}.device-gallery .laptop{max-width:245px}.device-gallery .smartphone{width:135px}.device-gallery .washer{width:210px}.device-gallery .hearing{width:210px}.device-facts{grid-template-columns:1fr}.fact summary{min-height:95px}.text-example{max-width:470px}.word-help dl{grid-template-columns:1fr 1fr}.thinking-note{padding:23px 21px}.footer{flex-wrap:wrap}.footer .credits{order:3;max-width:none;width:100%}}
@media(max-width:620px){body{font-size:1.03rem}.page{padding:0 19px}.topbar{padding:14px 0 12px;gap:12px;font-size:.82rem}.theme-toggle{font-size:.82rem;padding:6px 12px}.intro{padding:30px 0 25px;gap:15px;align-items:flex-start}.intro h1{font-size:clamp(2.5rem,10vw,3.2rem)}.intro-lead{font-size:1.04rem;margin-top:18px}.notebook-note{display:none}.intro .eyebrow{font-size:.69rem}.step-nav{gap:3px 13px;padding:11px 0 15px}.step-nav a{font-size:.88rem;gap:6px}.step-nav a span{width:25px;height:25px;font-size:.7rem}.lesson-section{padding:34px 0 38px}.section-heading{gap:12px;margin-bottom:19px}.section-heading .eyebrow{font-size:.67rem;letter-spacing:.08em}.step-number{font-size:2.1rem;margin-top:22px}.section-heading h2{font-size:1.55rem;line-height:1.28}.section-lead{font-size:1.04rem}.partner-hint{font-size:.92rem}.device-gallery{gap:22px 12px;margin:26px 0}.device-paper{height:170px;padding:10px 8px}.device-gallery .laptop{width:160px}.device-gallery .smartphone{width:89px}.device-gallery .washer{width:145px}.device-gallery .hearing{width:145px}figcaption{font-size:.96rem;margin-top:12px}figcaption small{font-size:.74rem}.think-first{padding:20px}.think-first .sentence-starter{font-size:1.4rem}.next-link{font-size:.94rem;gap:12px}.fact summary{padding:19px 17px;gap:10px}.fact-title{font-size:1.17rem}.open-hint{font-size:.7rem;gap:8px}.fact-content{padding:5px 18px 22px;font-size:.97rem}.text-example{padding:15px 10px;gap:6px}.example-word{font-size:1.4rem}.key-step kbd{font-size:.69rem}.word-help dl{grid-template-columns:1fr;gap:15px;padding:1px 20px 22px}.word-help summary{padding:15px 18px}.thinking-pair{grid-template-columns:1fr;gap:18px}.thinking-note blockquote{font-size:1.27rem}.discovery>summary{padding:21px 19px;font-size:1.12rem}.discovery-content{padding:3px 20px 23px;font-size:1.04rem}.discovery-content .key-sentence{font-size:1.34rem}.download-links{grid-template-columns:1fr}.footer{font-size:.76rem;gap:10px 20px}.footer>p{max-width:210px}.footer>a{margin-left:auto}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}}
@media print{:root,:root[data-theme="dark"]{--paper:#fff;--ink:#222;--muted:#444;--accent:#222;--apricot:#fff;--yellow:#f5f5f5;--surface:#fff;--border:#aaa;--line:#aaa;color-scheme:light}.page{max-width:none;padding:0}.topbar,.step-nav,.next-link,.take-away,.footer,.skip-link{display:none!important}.intro{padding:0 0 20px}.intro h1{font-size:32pt}.notebook-note{display:none}.lesson-section{padding:24px 0}.device-paper{height:150px}.device-gallery{grid-template-columns:repeat(4,1fr)}.device-gallery .drawing{max-height:130px}.device-gallery .smartphone{width:70px}.device-gallery .washer,.device-gallery .hearing{width:120px}.fact,.thinking-note,.discovery{break-inside:avoid}.device-facts,.thinking-pair{display:block}.fact,.thinking-note{margin-bottom:15px}.section-heading h2{font-size:19pt}.step-number{font-size:26pt}body{font-size:11pt}a{color:#222}details:not([open]){display:none}}